How is searching users different from listing them?

Listing returns every member; searching returns the ones matching a query. On a large platform, search is how an agent finds one specific person by name or handle without pulling and filtering the whole directory. List to enumerate, search to find.

What can an agent search by?

Typically a name, username, or part of an email, depending on the server. The query returns matching accounts, from which the agent picks the right user by id. GitHub and Gitea search platform accounts; Mattermost searches the workspace's members.

MCP servers that can search users

3 verified servers expose a tool that can search for users

Sometimes an agent does not need the whole roster, just one person: find the user who matches a name or a handle. Searching users returns the matches for a query, so an agent can resolve a specific person to their account without listing everyone.

These verified servers let an agent search for users by query.

Top pick

GitHub

Official

GitHub's official remote MCP server for repos, issues, pull requests, Actions, and code search.

version-control30,334

Tool:

search_users

GitHub's search_users queries user accounts across the platform, the way an agent finds a specific contributor by name or handle.

Pick 2

Gitea

Official

Gitea's official MCP server for repos, branches, issues, pull request reviews, releases, Actions, and wikis on any Gitea instance.

version-control73

Tool:

search_users

On a self-hosted Gitea instance, search_users finds accounts by query, the same targeted lookup on a forge you run yourself.

Pick 3

Mattermost

cloud.ru (community)

Community

A maintained MCP server for Mattermost that lets agents work with channels, messages, threads, reactions, users, teams, and files.

communication30

Tool:

search_users

Mattermost scopes search_users to the workspace, returning the members matching a query so an agent can resolve one to mention or message.

What to know

Search is the targeted counterpart to listing: instead of pulling every member, an agent asks for the ones matching a name, a username, or part of an email. The three servers here run that query against their user directories, GitHub and Gitea across accounts on the platform, Mattermost across the workspace. It returns the matching users so the agent can pick the right one to mention, assign, or look up. On a large platform this is far cheaper than enumerating everyone and filtering after the fact.

When an agent keeps resolving the same handful of people, remembering the matches it already found saves the repeat search. A person it interacts with regularly is worth holding by id, so it goes straight to the right account rather than searching the directory again each time.

Questions

How is searching users different from listing them?: Listing returns every member; searching returns the ones matching a query. On a large platform, search is how an agent finds one specific person by name or handle without pulling and filtering the whole directory. List to enumerate, search to find.
What can an agent search by?: Typically a name, username, or part of an email, depending on the server. The query returns matching accounts, from which the agent picks the right user by id. GitHub and Gitea search platform accounts; Mattermost searches the workspace's members.